This invention relates to viewing systems suitable for operation in dark or in dimly lit surroundings, using infrared or low level visible light as the input. The purpose of the system is to provide high gain to make a faint visible image or an infrared image readily seen as a visible image for direct viewing, copying, storing, transmitting and the like.
Devices generally known as image intensifiers are used for this purpose at the present time. These devices utilize phosphors for producing an intensified visible image and encounter severe limitations on gain and noise. Typically the gain per unit is less than 500 and a plurality of units will be used in cascade to provide the necessary output intensity. Accordingly, it is an object of the present invention to provide a new and improved viewing system for use with low radiation level inputs which will have relatively low noise and relatively high gain permitting use of single stage devices. A further object is to provide such devices which can incorporate image intensifiers.